Lindbergh traveled widely and developed an interest in the cultures of peoples in Africa and the Philippines. In the late 1960’s, he ended his years of silence to speak out for the conservation movement. He especially campaigned for the protection of humpback and blue whales, two species of whales in danger of extinction. Lindbergh opposed the development of supersonic transport planes because he feared the effects the planes might have on the earth’s atmosphere. Here is a link to a much larger article about his conservation efforts.